Sorption of dibasic acids on weak base resins

Higher rates of uptake of dibasic acids by weak base anion exchange resins, in comparison to those of monobasic acids, have been satisfactorily explained on the basis of dual site adsorption of divalent anion on the protonated resin sites. Due to dual site sorption, divalent anions are strongly bound to the resin matrix, thereby neutralizing the positive charges on the protonated pore surface. Hence, there is practically no exclusion of co-ions from the pores of the resin. The extent of reversibility of sorption is considerably less as a result of less repulsion of H+ ions from the pore surface than that observed in monobasic acids. A theoretical model is developed and successfully validated using the experimental data of our work and those in the literature on batch sorption dynamics of sulfuric acid on weak base resins.